Question

A cylindrical water tank 1.5 m in diameter and 2.5 m high is surrounded on both ends and the sides with RSI =3 insulation. It is desired to keep the water at 80 degrees C, while the ambient temperature is 20 degrees C. WHat is the minimum RSI- value that is required for the walls and roof?

Answer 1

Ans) Given,

Diameter of tank = 1.5m

Height of tank = 2.5m

RSI value of material surrounding tank = 3

Temperature difference (T) = 80 - 20 or 60^oC

Minimum RSI value required = Surface area x T / Heat loss per hour

Given that tank is surrounded with RSI 3 material at wall and both ends

Total area = dh + 2 x(/4) d²

= 15.30 m²

therefore,

3 = 15.30 x 60 /heat loss

heat loss = 306 W

  Surface area of wall and roof = dh + (/4)d²

= (3.14)(1.5)(2.5) + (3.14/4) x1.5x1.5

= 13.55 m²

Minimum RSI value required = 13.55 x 60 / 306

= 2.65 m^2oC /W